552 



DKVELOPMENT OF THE N.O. MYRTACEJE, 



meae, and the other by the Metrosidereae. For the Metrosidereae, 

 the transition from the Myrteae is suggested by Backhousia and 

 Osbomia, which have capsular but indehiscent fruits. The transi- 

 tion to Euleptospermeae is not at all well denned, and the earlier 

 forms appear to be extinct. The Leptospermeae are possessed of 

 long and often richly-coloured stamens, but some of the genera 

 possess well-marked nerves, whereas the Metrosidereae contain no 

 nerved leaves. The Euleptospermeae, moreover, are not often pos- 

 sessed of opposite leaves. 



After the evolution of JBceckea, Leptospermum, Melaleuca, Cal- 

 listemon, Metrosideros, Tristania, Syncarpia, Xanthostemon, and 

 others, there was a tendency to disperse from the Australian centre. 

 The Leptospermeae, with the exception of Metrosidereae, suggest an 

 adaptation to the poor soil, and more temperate and dry climate 

 of the main continent ; while the Metrosidereae are closely allied to 

 the Myrteae, and were unable to push their way southwards. In 

 the same way, the Leptospermeae, with the exception of the Metro- 

 sidereae, were not well adapted to compete with the Asiatic vegeta- 

 tion in the fertile tropics. The Metrosidereae thus had a better 

 chance of being distributed throughout the long, narrow, fertile 

 land-connections with Fiji, New Caledonia, New Zealand and Asia. 

 On the other hand, the only chance which presented itself for the 

 distribution of the remainder of the Leptospermeae in these direc- 

 tions, was the infrequent existence of poorer soils existing to the 

 north and east. 



From these considerations, it is evident that the chances of dis- 

 tribution for the Metrosidereae throughout what is now the Malay 

 Archipelago, New Caledonia, and New Zealand, were much greater 

 than for the remainder of the Leptospermeae; and when one finds 

 Bceckea in the Malay Islands, Southern China, Sumatra, Malaya 

 and New Caledonia (5 species) ; Leptospermum in the Malay 

 Islands, Burmah, Malaya, and New Zealand (3 species) ; Melaleuca 

 in New Caledonia, the Malay Islands, New Zealand, and Tahiti; 

 Callistemon in New Caledonia; while Metrosideros occurs in New 

 Zealand, New Caledonia, the Moluccas, South Africa (?), Java, 

 Tahiti (?), Chili (?), Lord Howe Island, Madagascar (?), and the 



